1. Field of the Invention
The invention relates to an input sensing system, and more particularly to a three-dimensional input sensing system.
2. Description of the Related Art
Referring to FIG. 1, a conventional input sensing system comprises a three-dimensional (3D) input device 1 and a host 2. The 3D input device 1 has a plurality of 3D motion sensing units, such as a gyroscope 11, an accelerometer 12 and an electronic compass 13. The 3D input device 1 further has a micro controller 14, which includes a computing unit 15, a power managing unit 16 and a radio frequency (RF) transceiver unit 17, and a rechargeable battery 18. The host 2 includes a RF transceiver unit 21 and a central processing unit (or a micro controller) 22.
The 3D motion sensing units 11, 12, 13 detect motion of the 3D input device 1 and generate sensing signals corresponding to motion detected thereby. The computing unit 15 receives the sensing signals from the 3D motion sensing units 11, 12, 13, and performs computation processing upon the sensing signals so as to obtain 3D coordinate information of the 3D input device 1. The central processing unit 22 of the host 2 receives the 3D coordinate information via the RF transceiver units 17, 21, and performs an action corresponding to the 3D coordinate information. According to the 3D coordinate information of the 3D input device 1 obtained by the computing unit 15, the power managing unit 16 of the 3D input device 1 determines whether the 3D input device 1 has remained motionless for a predetermined time period. If affirmative, the power managing unit 16 stops supply of power from the battery 18 to the computing unit 15 and the RF transceiver unit 17. Subsequently, when the 3D motion sensing units 11, 12, 13 detect movement of the 3D input device 1, the power managing unit 16 resumes supply of power from the battery 18 to the computing unit 15 and the RF transceiver unit 17. Hence, power of the battery 18 may be conserved.
Because the battery 18 serves as the power source of the 3D input device 1, power resource of the 3D input device 1 is limited. Since the computing unit 15 in the 3D input device 1 consumes a lot of power when performing computations, power of the battery 18 of the 3D input device 1 is quickly used up, resulting in a shorter battery life.